Computer users are accustomed to using a mouse and keyboard as a way of interacting with a personal computer. While personal computers provide a number of advantages over printed documents, users often continue to perform certain functions using printed paper. Some of these functions include reading handwritten documents. In the case of annotations, the printed document assumes a greater significance because of the annotations placed on it by the user. One of the difficulties, however, with having a hand-written document is a later need to have the content entered back into the electronic form of the document. This requires the original user or another user to wade through the handwritten content and enter them into a personal computer. In some cases, a user will scan in the handwritten content and the original text, thereby creating a new document. These multiple steps make the interaction between the printed document and the electronic version of the document difficult to handle on a repeated basis. Further, scanned-in images are frequently non-modifiable. There may be no way to separate the handwritten content from the original text. This makes using the handwritten content difficult. Accordingly, an improved way of handling handwritten content is needed.
Tablet PC's are increasingly being used to capture and display handwritten content. In the context of taking notes during a meeting, for example, a Tablet PC presents less of a barrier between individuals than does a laptop computer. Tablet PC's also allow for capturing of handwritten notes so that Tablet PC users are able to take notes in their own handwriting, in an unobtrusive manner similar to taking handwritten notes with a pen and paper.
Tablet PC's capture and display digital ink. The term “digital ink” refers to one or more strokes that are recorded from a pointing device, such as a mouse, a stylus/pen on a digitizer tablet, or a stylus/pen on a display screen integrated with a digitizer tablet (e.g., a touch-sensitive display screen). As used herein, the term “ink” is shorthand for digital ink.
Documents displayed on writing surfaces of tablet PCs may be annotated by a user. Correspondingly, annotations such as underline and blobs are often incorporated within the document. For example, a user may underline a few words in a document to emphasize the words underlined. Thus, extraction of handwritten annotations plays an important role in document processing.